Age

18–any

Sex

ALL

Healthy volunteers

Not accepted

In order to be eligible to participate in this study, a subject must meet all of the following criteria:
Hospitalization primarily because of severe acute exacerbation of COPD
Spirometry record within last 5 years, with: post-bronchodilator FEV1/FVC \< 0,70 and FEV1% \< 80%predicted
Minimum of 10 packyears

A potential subject who meets any of the following criteria will be excluded from participation in this study:
Established diagnosis of diaphragm diaphragm paralysis.
Inability for diaphragm imaging (e.g. mechanical ventilation, or unable to follow vocal instructions).
Those not able or unwilling to give written informed consent.
Pregnant women

Ultrasound of the Diaphragm Excursion Ratio as Physiological Biomarker in Acute Exacerbations of Chronic Obstructive Pulmonary Disease